Conventional magnetic disk drives are information storage devices which utilize at least one rotatable magnetic media disk with concentric data tracks, a read/write transducer for reading and writing data on the various tracks, an air bearing slider for holding the transducer adjacent to the track generally in a flying mode above the media, a suspension for resiliently holding the slider and the transducer over the data tracks, and a positioning actuator connected to the suspension for moving the transducer across the media to the desired data track and maintaining the transducer over the data track during a read or a write operation.
The recording density of a magnetic disk drive is limited by the distance between the transducer and the magnetic media. One goal of air bearing slider design is to "fly" a slider as closely as possible to a magnetic medium while avoiding physical impact with the medium. Smaller spacings, or "fly heights", are desired so that the transducer can distinguish between the magnetic fields emanating from closely spaced regions on the disk.
In addition to achieving a small average spacing between the disk and the transducer, it is also critical that a slider fly at a relatively constant height. The large variety of conditions the transducers experience during the normal operation of a disk drive can make constancy of fly height anything but a given. If the flying height is not constant, the data transfer between the transducer and the recording medium may be adversely affected.
The manner in which a slider is manufactured and the material the slider is fabricated from can affect fly height. It is also essential that variations in the physical characteristics of the slider, e.g. due to manufacturing tolerances, not substantially alter the flying height of the slider. If this result is not achieved, the slider's nominal fly height must be increased to compensate for variations between sliders.
In forming the slider, processes known to those skilled in the art are generally used. For example, the slider may be coated with a photoresist which is developed to allow for patterning of the slider. The slider may then be patterned by means such as ion beam etching or chemical plasma etching. For example, Japanese Patent No. 07-078804 discloses an ion beam etching process used to provide a thin film magnetic head. The mixing ratio of mixed gas is set so that an organic coating film and an inorganic insulating film are etched at the same rate. Japanese Patent No. 9145325 discloses a reactive ion etching process which comprises introducing CHF.sub.3 and Ar gases at a flow ratio of 1:5 or more. The pressure inside the vacuum chamber is maintained at 0.3 Pa or lower to generate plasma for reactive ion etching (RIE).
Japanese Patent No. 08-170181 discloses a dry etching process for tungsten intended to enhance the uniformity of etching rate in the surface of a wafer by using a gaseous mixture of sulfur hexafluoride with Ar when tungsten is dry-etched. Japanese Patent No. 4-129217 discloses a sputter etching process using argon gas that enables cleaning while redeposits in a through hole are removed.
All of Chen, et al, U.S. Pat. No. 5,461,010, Terkado, U.S. Pat. No. 5,183,531, Nagano, et al, U.S. Pat. No. 5,234,537, and Blalock, U.S. Pat. No. 5,286,344 also disclose etching processes which may be used for various substrates. For example, Charlet et al, U.S. Pat. No. 5,047,115 discloses a process for etching a substrate with the aid of a gas plasma produced either by ultra-high frequency waves, or by ultra-high frequency and radio-frequency waves. However, Charlet et al does not contemplate the etching of ceramics or obtaining enhanced smoothness through the use of tertiary etchant gas mixtures, applied to composited ceramics.
These publications reflect a broad base of teaching concerning the use of etching in the formation of various substrates. However, these etchings do not contemplate the problems of smoothness, rate, and definition among other concerns of ceramics of binary (or greater) composition.
As a result, there is a need for methods which will provide reactive ion etching of ceramic substrates with reliable smoothness, rate and definition.